I actually have a theory about this...

A friend of mine came back to the game after many months long break and his games were like yours - full of bots, a dozen players max. I didn't believe him as my experience was completely different. So logged with my alt account I didn't use since last summer and it was it - the games were almost exclusively bots. I had like 4 wins every six game. But then, about a week later, my games turned back to normal with 20% of bots max. But the friend of mine still plays with mostly bots. If we would play duo, we made sure he was the leader as the games were easier that way.

Therefore, I think there is some sort of stats-based matchmaking where "easy mode" gets mostly bots. In order to move up to a players-only tier try to get as good stats as you can.